The Ridley Kanzo Fast GRX800 1x12s embodies the quintessence of racing gravel bikes: a machine that merges cutting-edge aerodynamics inherited from the Noah Fast with the versatility and comfort demanded by the most challenging gravel routes. Voted best gravel racing bike of 2023 by Gran Fondo magazine, this high-end carbon model equipped with the Shimano GRX800 1x12-speed mechanical groupset pushes the boundaries of off-road performance, delivering a riding experience that is fast, responsive and surprisingly comfortable.

Technical Summary

The Kanzo Fast is built on a 30T HM/HR UD carbon frame that combines high bottom bracket stiffness with vertical compliance. With a weight of 1190 g in size M (frame only with paint) and a fork weighing 490 g, the complete bike in GRX800 configuration ranges between 8.5 and 9.2 kg depending on components. The F-Tubing architecture integrates truncated NACA profiles for a measured aerodynamic gain of 17 watts compared to traditional gravel bikes, while maintaining generous tire clearance of 700c x 42 mm. The F-Steerer D-shape head tube accommodates fully integrated cabling, while the lowered chainstays and D-Shape aero seatpost with 6 mm offset maximize vibration absorption.

Technical Highlights

• WorldTour-level aerodynamics: Derived from the Noah Fast, the Kanzo Fast exploits NACA-shaped tubes, a seamless fork-frame junction, a D-shape head tube and an aero seatpost to reduce drag. Wind tunnel tests confirm optimal efficiency between 25 and 30 km/h, yaw angles from 0 to 15°.
• Reliable Shimano GRX800 1x12-speed mechanical groupset: The Shimano GRX RX822 rear derailleur with medium cage (45T compatible) integrates a Shadow RD+ clutch for chain security on rough terrain. Single 42T chainring paired with an XT 10-45T cassette (Microspline) offering a 490% gear range to tackle climbs and brutal accelerations.
• Multi-modulus Elite Series carbon: Selective 24T, 30T, 50T and 60T Torayca layup to balance stiffness and comfort. Ultra-rigid bottom bracket for immediate power transfer, combined with preserved vertical compliance thanks to low chainstays and high-modularity carbon.
• Performance wheels and tires: DT Swiss G1800 Spline Tubeless Ready wheels (25 mm depth, 24 mm internal width) fitted with Vittoria Terreno Dry TLR 700x38-40c tan sidewall tires, configured for speed on fast paths and grip on dry gravel.
• Gravel-specific integrated cockpit: Forza Gravel Integrated carbon handlebar with integrated stem (lengths 90 to 120 mm, widths 380 to 460 mm depending on size), 16° flare, 120 mm drop, 70 mm reach. Ergonomics designed for gravel handling and long-distance comfort.
• Progressive gravel racing geometry: Long wheelbase (~1017-1053 mm depending on size), progressive reach (373-400 mm), 71-72° head angle for high-speed stability, constant short chainstays at 425 mm across all sizes for agility and maneuverability.
• Shimano GRX hydraulic braking: BR-RX820 Flat Mount calipers paired with RT-MT800 Centerlock 160 mm rotors (Freeza technology), precise modulation and high power, 10% wider pad clearance for muddy conditions.

Versatility and Comfort

While designed for gravel racing, the Kanzo Fast doesn't forget comfort. The lowered chainstays, the D-Shape seatpost with F-Surface Plus technology and the carbon's compliance effectively filter vibrations on gravel and rough paths. The 42 mm tire clearance allows for voluminous tires to absorb shocks and roll fast on all types of surfaces. Fender mounting points (fork and frame) add a touch of versatility for winter rides or light bikepacking.

Sizes and Adjustments

The Kanzo Fast GRX800 is offered in five sizes (XS, S, M, L, XL) covering riders from 158 cm to over 195 cm. Each size benefits from a matched integrated handlebar (stem length 90-120 mm, handlebar width 380-460 mm), adjusted crank lengths (170-175 mm) and calibrated stack/reach geometry to maintain balanced handling, regardless of stature. The total weight limit (rider + equipment + bike) is set at 110 kg.

Positioning and Use

The Ridley Kanzo Fast GRX800 1x12s is aimed at competitive gravel riders and experienced cyclists seeking an ultra-high-performance bike for fast and hilly courses. Its aero DNA and racing geometry make it a formidable weapon for gravel races, mixed road-gravel sportives, and long high-cadence rides on rolling paths. Less suited to extreme technical singletrack, it excels on fast gravel, forest tracks, farm roads and paved sections where speed is paramount.

Heritage and Recognition

Launched in 2020, the Kanzo Fast quickly conquered the international gravel scene. Voted best gravel racing bike 2023 by Gran Fondo magazine, the jury praised "a majestic combination of aero optimization and comfort, enabling not only professionals to fly on the world's gravel roads, but also gravel beginners to surpass themselves." This recognition confirms the success of Ridley's strategy: transferring the Noah Fast's achievements to a gravel frame without compromising comfort or versatility.